Phenolic coupler compound



Patented Jan. 4, 1944 PHENOLIC COUPLER COMPOUND Paul W. Vittum and Willard D. Peterson, Rochester, N. Y., assignors to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey No Drawing. Application December 12, 1941,

Serial No. 422,699

9 Claims.

This invention relates to photographic color forming or coupling compounds and particularly to substituted phenolic coupler compounds.

The formation of colored photographic images by using a primary aromatic amino developing agent which couples with a color forming compound on development has been the subject of numerous prior patents. Most of these patents have been directed to coupler compounds which produce on development dyes which meet the requirements of subtractive color photography, that is, dyes which are colored yellow, magenta or blue-green.

Phenolic coupler compounds have been described in prior patents such as Fischer U. S. Patent 1,055,155, March 4, 1913, Mannes and Go dowsky U. S. Patent 2,039,730, May 5, 1936, and French Patent 836,144. French Patent 836,144 discloses 2,5-dialkylphenols such as thymol as couplers. The known 2,5-dialkylphenols, however, produce pure blue dyes with the commonly used dialkyl-p-phenylene-diamine developers and such dyes do not have the proper absorption characteristics for use in color photography. Some of the dyes produced therefrom also are objectionable in that they are readily decomposed by heat and light. I

It is, therefore, an object of the present invention to provide novel coupler compounds for color photography. A further object is to provide phenolic coupler compounds having the proper spectral absorption characteristics for use in multicolor photography. A still further object is to provide coupler compounds which form photographic images having satisfactory heat and light stability characteristics. Other objects will appear from the following description of our invention.

These objects are accomplished by the use of primary aromatic amino developing agents in conjunction with certain 2,5-disubstituted phenols as coupler compounds. These coupler compounds have substituents in the 2- and 5-positions with respect to the phenolic hydroxyl group, one of the substituents being an alkyl or alkenyl group and the other substituent being an aminoalkyl, alkoxy, alkenyl or substituted alkenyl oup.

The following compounds illustrate couplers suitable for use according to Our invention:

CH1CH=CH2 2-allyl-5-methylphenol C H: O H- C H:

2-propenyl-5-methylphenol 10 C H-CH=C H2 OHs- CH3 2-allyl-3, 5-dimethylphenol O H: C H- C H;

CH3 CH3 2-propenyl-3,5-dimethylphenol OH OH I I I CH=UH I CHa- CH3 2,2'-dihydroxy-4,4-dimethyl-5,5-dichlorostilbene The following example, which is illustrative only, is a developing solution compounded accordme to our invention:

A. 2-amino-5-diethylamino toluene HCl grams 2 Sodium sulfite do 5 Sodium carbonate do 30 Water to liter 1 B. 2-allyl-5-methyl phenol grams 2 Sodium hydroxide (10% solution) cc 10 In use, B is added to A.

In addition to their use in the developing solution, as is the abov example, the coupler compounds of our invention may be incorporated in the photographic layer prior to exposure and the colored image formed by development in a'primary aromatic amino developing solution. Special dispersing agents may be used for incorporating the coupler compound in the emulsion and in certain cases the coupler compound may be absorbed or adsorbed to the sensitive salt or may be combined with the sensitive silver salt; of a chemical combination. In the case of mul'ti-layer photographic film in which the color-forming compounds of our invention may be incorporated in one of the emulsion layers, the coupler molecule may be suitably enlarged to render it non-diffusing in the gelatin.

The aromatic amino developing agents used with the coupler compounds of our invention include the mono, diand tri-aminoary1 compounds and their derivatives formed by substitution in the amino group as well as in the ring such as alkyl phenylene diamines and alkyl toluylenediarnines. These compounds are usually employed in the salt form such as the hydro chloride or the sulfate which is more stable than the amines themselves. Suitable compounds are diethyl p phenylenediamine hydrochloride, monomethyl-p-phenylenediamine hydrochloride, and dimethyl-pphenylenediamine sulfate. The p-aminophenols and their substitution products may also be used Where the amino group is unsubstituted. All of these developing agent have an unsubstituted amino group at which the oxidation products of the developer couple with the color forming compounds to form dye images.

As stated above, the coupling compounds used according to our invention produce dyes which are greenish-blue in color and hence are suitable for use in three color subtractive processes of color photography. These compounds have been found to yield dyes which are more stable to heat and light than those produced from the corresponding phenols in which the -position rela tive to the hydroxyl group carries no substituent.

In addition to the Substituents in the 2- and 5-positions with respect to the phenolic hydroxyl group, the coupler used according to our invention may also have other substituents such as halogen, alkyl, etc., in other positions in the molecule as illustrated by Examples 3 to 5. The additional substituents illustrated in Examples 3 to 5 have not been found to confer increased stability upon the resulting dyes but may be used for purposes of altering the color of the dyes or changing their solubility and diffusion charac teristics or the solubility and diffusion characteristics of the original couplers.

Our development process may be employed for v the production of colored photographic images in layers of gelatin or other carrier such as collodion, organic esters of cellulose, or synthetic resins. The carrier may be supported by a transparent medium such as glass, cellulose ester, or a non-transparent reflecting medium such as paper or an opaque cellulose ester. The emulsion may be coated as a single layer or as multiple layers on the support or in the case of a transparent support as superposed layers on both sides of the support. The superposed layers may be differentially sensitized and th dyes formed therein by coupling may be bleached by an oxidizing agent such as chromic acid to colorless soluble compounds. The destruction of the dye in this Way does not destroy the silver image and the silver may be resensitized to develop a color a number of times thus permitting the formation of natural color images in superposed layers as described, for example, in Mannes and Godowsky U. S. Patent 2,113,529. Colored images may also be formed in the manner described in Mannes, Godowsky and Wilder U. S. Patent 2,252,718.

The examples and compounds set forth in the present specification are illustrative only and it is to be understood that our invention is to be taken as limited only by the scope of the appended claims.

We claim:

1. A color forming photographic developer comprising a primary aromatic amino developing agent and a phenol coupler having an alkyl substituent in one of the positions selected from the class consisting of the 2- and 5-positions with respect to the phenolic hydroxyl group and an alkenyl substituent in the other of said positions.

2. A. color forming photographic developer comprising a primary aromatic amino developing agent and a phenol coupler having a methyl group in the 5-pos-ition with respect to the phenolic hydroxyl group and having an alkenyl substituent in the 2-position with respect to the phenolic hydroxyl group.

3. A color forming photographic developer comprising a primary aromatic amino develop ing agent and a phenol coupler having an allyl substituent in the 2-position and an alkyl substituent in the 5-position with respect to the phenolic hydroxyl group.

l. A color forming photographic developer comprising a primary aromatic amino developing agent and 2-allyl-5-methyl phenol as a coupler.

5. The method of producing a colored photographic image in a gelatino silver halide emulsion layer which comprises exposing and developing it and simultaneously with the development coupling the development product of a primary aromatic amino developing agent in the presence of the developed image with a phenol coupler having an alkyl substituent in'one of the positions selected from the class consisting of the 2- and 5-positions with respect to the phenolic hydroxyl group and an alkenyl substituent in the other of said positions.

6. The method of producing a colored photographic image in a gelatino silver halide emulsion layer which comprises exposing and developing it and simultaneously with the development coupling the development product of a primary aromatic amino developing agent in the presence of the developed image with a phenolic coupler compound having an allyl group in the 2-position and an alkyl group in the 5-position with respect to the phenolic hydroxyl group.

7. The method of producing a colored photographic image in a gelatino silver halide emulsion layer which comprises exposing and developing it and simultaneously with the development coupling the development product of a primary aromatic amino developing agent in the presence of the developed image with a Z-allyl-S- methyl phenol.

8. A photographic emulsion for forming colored images comprising a carrier containing a sensitive silver halide and a phenol coupler having an alkyl substituent in one of the positions selected from the class consisting of the 2- and 5-positions With respect to the phenolic hydroxyl group and an alkenyl substituent in the other of said positions.

9. A color forming photographic layer comprising a gelatino silver halide emulsion containiing a phenol coupler having an alkyl substituent in one of the positions selected from the class consisting of the 2- and 5-positions with respect to the phenolic hydroxyl group and an alkenyl substituent in the other of said positions.

PAUL W. VITTUM. WILLARD D. PETERSON. 

